Issue #357 - Do not truncate results of integer division

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## 0.15 - TBD
 
+Bug Fixes
+
+- Prevent truncation when dividing two fixnums.
+
 ## 0.14 - February 11, 2020
 
 Cyclone now automatically relocates any stack objects when performing a mutation. This prevents a whole range of race conditions that had previously been possible in multithreaded application code. And since this work is done by the Cyclone runtime no special code needs to be added to your applications.

runtime.c

@@ -3969,7 +3969,6 @@ object Cyc_fast_mul(void *data, object ptr, object x, object y) {
 }
 
 object Cyc_fast_div(void *data, object ptr, object x, object y) {
-  int z;
   // x is int (assume value types for integers)
   if (obj_is_int(x)){
     if (obj_is_int(y)){
@@ -3977,8 +3976,8 @@ object Cyc_fast_div(void *data, object ptr, object x, object y) {
       // Overflow can occur if y = 0 || (x = 0x80000000 && y = -1)
       // We already check for 0 above and the value of x above is a
       // bignum, so no futher checks are required.
-      z = obj_obj2int(x) / obj_obj2int(y);
-      return obj_int2obj(z);
+      assign_double(ptr, (double)(obj_obj2int(x)) / obj_obj2int(y));
+      return ptr;
     } else if (is_object_type(y) && type_of(y) == double_tag) {
       assign_double(ptr, (double)(obj_obj2int(x)) / double_value(y));
       return ptr;